A220625 Number of ways to reciprocally link elements of an 6Xn array either to themselves or to exactly one horizontal, diagonal and antidiagonal neighbor

1, 733, 28373, 3466455, 262680517, 24177895648, 2054706174413, 180411767818111, 15630369162961753, 1361611598697855401, 118348460320274885509, 10296062072472866977053, 895398179175506044479552

Offset

1,2

Comments

Row 6 of A220621

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 63*a(n-1) +2862*a(n-2) -60440*a(n-3) -824202*a(n-4) +18146150*a(n-5) -20045386*a(n-6) -921241585*a(n-7) +3855313257*a(n-8) +9737277088*a(n-9) -97429928112*a(n-10) +108733427540*a(n-11) +757492139660*a(n-12) -1932297359512*a(n-13) -1293178837092*a(n-14) +7244830922052*a(n-15) -3341781023928*a(n-16) -7386155450412*a(n-17) +15850519492508*a(n-18) -14572332601872*a(n-19) -15900073555920*a(n-20) +32949026690632*a(n-21) -1615780730832*a(n-22) -14531450950368*a(n-23) +3100647563872*a(n-24) +425129425324*a(n-25) -23935477836*a(n-26) +300359574120*a(n-27) +63008127325*a(n-28) +37808128429*a(n-29) -35095894230*a(n-30) -6841941084*a(n-31) -750501810*a(n-32) +796187034*a(n-33) -8202438*a(n-34) -1789695*a(n-35) -552825*a(n-36)

Example

Some solutions for n=3 0=self 1=nw 3=ne 4=w 6=e 7=sw 9=se (reciprocal directions total 10)
..0..6..4....6..4..0....0..6..4....0..0..0....0..9..0....0..0..0....9..6..4
..0..0..0....6..4..0....9..9..0....0..9..0....9..7..1....0..0..0....0..1..7
..0..7..0....0..0..0....0..1..1....0..7..1....3..1..7....6..4..0....0..3..0
..3..7..0....9..7..0....6..4..7....3..0..0....0..3..0....6..4..7....0..6..4
..3..0..0....3..1..0....0..3..0....9..7..0....0..7..0....0..3..0....0..6..4
..6..4..0....0..6..4....0..6..4....3..1..0....3..0..0....0..0..0....0..6..4

Crossrefs

Sequence in context: A166607 A346024 A297761 * A260035 A033529 A118055

Adjacent sequences: A220622 A220623 A220624 * A220626 A220627 A220628

Keyword

nonn

Author

R. H. Hardin Dec 17 2012

Status

approved